The Primate Core (Core B) is proposed to manage the P01-dedicated primate colony and associated investigations. There are four aims for this Core: Aim 1: to provide rhesus oocytes, sperm and embryos produced by sophisticated methods of assisted reproduction (ART) to PO1 investigators, and DNA for sequencing NHP genomic imprints; Aim 2: to establish pregnancies for epiblast and primordial germ (PG) cell isolations by natural mating and ART; to establish and support control and chimeric pregnancies;and to monitor established pregnancies to ensure successful outcome;Aim 3: to provide neonatal intensive care (NICU) for premature and/or sick primate chimeric infants;to provide intensive developmental and behavioral assessments on neonates, juveniles and adolescent primates to assess pediatric outcome;and to maintain autologous and heterologous primates for in vivo studies; and Aim 4: to prepare, support, and transport primates with chimeric pregnancies and after ES cell transplantation, for MRI imaging. Each subproject requires significant investigations using nonhuman primates and the success of this program relies on Core B providing the optimal specimens, procedures and analyses in timely, accurate and reliable fashions. Core B supports: Subproject I by providing staged embryos, and embryos derived by SCNT for the production of chimeras for both in vitro and in vivo analyses, performing embryo transfers, and providing MFM, neonatology and pediatric care and assessments of offspring;Subproject II by providing timed pregnant primates suitable for transplantation of differentiated ES cells into juvenile or adult primates, performing injections of differentiated stem cells into animals, monitoring for adverse effects and cell engraftment via ultrasound;and Subproject HI by providing the primordial germ cells collected from fetal macaques both prior to, and after, their entry into the fetal gonads, staged embryos for the production of EG chimeras for in vitro and in vivo analyses and MFM, neonatology and pediatric care and assessments of offspring. The core also provides specimens for project Ill's sequencing of the imprinted genes homologous to human imprinted regions, for which polymorphisms within the primate colony are being identified.